Multimedia distribution systems are becoming increasingly important vehicles for delivering video, audio and other data to and from remote users. Such distribution systems include cable or community access television (CATV) systems, telephone systems and computer networks. A set top box may be used as an interface between the distribution system and a television set, computer or other type of remote user terminal. The set top box typically provides functions such as input/output processing of video, audio and other data, audio and video demultiplexing and decompression, graphics overlay processing for use in electronic program guides and the like, entitlement control for video on demand (VOD), near video on demand (NVOD) and pay-per-view (PPV) applications, and remote control user interfaces.
A conventional set top box generally provides the above-noted functions using a multiplicity of dedicated stand-alone integrated circuits, each having its own separate support circuitry and protocols to provide, for example, memory access and other processing functions. This may be attributed in part to the fact that many of the circuits used in set top box applications are general-purpose devices designed to support a broad array of applications. As a result, there is considerable overlap in many of the circuit functions, as well as potential incompatibilities which lead to slower processing speed and other inefficiencies. The conventional set top boxes are therefore not only unduly complex and expensive, but also fail to provide optimal levels of performance. Widespread implementation of multimedia distribution systems using cable, telephone and/or computer networks will depend in large part upon reducing the complexity and cost of set top box hardware.
As is apparent from the above, there is a need for an improved processing system suitable for use in set top box applications and which can be configured to utilize shared processing hardware to thereby provide video, audio, graphics, input/output communication and other functions with improved efficiency and reduced cost and complexity.